Ethnic differences in aortic pulse wave velocity occur in the descending aorta and may be related to vitamin D

Area of Science:

• Cardiovascular Science
• Nutritional Epidemiology
• Biomarkers of Cardiovascular Risk

Background:

• Aortic pulse wave velocity (aPWV) predicts cardiovascular events independently of blood pressure.
• Ethnic variations in coronary heart disease risk are observed, with South Asians typically at higher risk.
• The roles of vitamin D and aldosterone in aortic stiffness across ethnic groups require further investigation.

Purpose of the Study:

• To investigate the association between blood levels of vitamin D and aldosterone with total and regional aortic stiffness.
• To examine ethnic differences in aortic stiffness (aPWV) among British men of South Asian, African Caribbean, and European descent.
• To determine if vitamin D or aldosterone levels mediate ethnicity-related differences in aPWV and cardiovascular risk.

Main Methods:

• Noninvasive estimation of total aPWV using the Arteriograph device (aPWV(AG)) in 198 men.
• Magnetic resonance imaging (MRI) to measure aPWV over the aortic arch and descending aorta in a subsample (n=47).
• Measurement of serum 25-hydroxyvitamin D (25(OH)D) and aldosterone levels, with statistical adjustments for age, blood pressure, and diabetes.

Main Results:

• South Asian men exhibited significantly higher aPWV(AG) compared to African Caribbean and European men, adjusted for cardiovascular risk factors.
• MRI confirmed higher PWV in the descending aorta of South Asians, but not in the aortic arch.
• Lower serum 25(OH)D levels were found in South Asian and African Caribbean men compared to Europeans.
• Serum 25(OH)D, but not aldosterone, was negatively correlated with aPWV(AG) and attenuated ethnic differences in aPWV.

Conclusions:

• Aortic stiffness, particularly in the descending aorta, parallels coronary heart disease risk across ethnic groups.
• Serum 25(OH)D is an independent negative correlate of aortic stiffness (aPWV).
• Vitamin D deficiency may partly explain the observed ethnicity-related differences in aortic stiffness and cardiovascular risk.